MALACOFAUNA OF THE WAWEL HILL IN CRACOW

A molluscan assemblage compns1ng 21 species was found at the Wawel Hill in the centre of Cracow. Three types of associations were distinguished using simple numerical methods. Their composition and distribution are controlled both by natural ecological conditions and by the influence of cultivation, grazing and pollution. The mentioned factors are also responsible for the differentiation of the ~hell size in particular populations. At the foot of the hill the allocenose of molluscs accumulated by flood of the Vistula river was observed. THE OCCURENCE OF MOLLUSCAN ASSEMBLAGES The castle of Wawel is situated in the centre of Cracow, at a limestone hill, about 40 m over a built-~p area of the Vistula valley. The steep slopes of the hill are covered with cultivated grass but in some Places, mainly at the West, NorthWest and East sides, there are rocky slopes, overgrown partly with bushes and deciduous trees. On the flat ridge-crest of the hill, surrounded by walls and towers, the old royal castle, the Wawel-Cathedral and some less old buildings are risen up. Among these there are lawns and flower-beds with introduced garden plants. These artificial anthropogenic habitats as well as an intensive traffic and a remarkable air and soil pollution cr~ate the unfavourable conditions for t~e developement of the fauna, however, the molluscan assemblages found here are sufficiently rich and differentiated to be interesting as a subject of a detailed study.

Like the molluscs from other sites of the town of Cracow the malacofauna of the Wawel Hill has not been described in detail so far .A progressing pollution and changes in the natural environment in Poland make it necessary to study, like in other ~untries, the pr.esent conditions of the malacofauna living in towns.Snails and their empty shells were collected by the author at the Wawel Hill during three years (1983)(1984)(1985), mainly in spring and autumn.Each of the nine sites described was visited 5-8 times.Besides the samples of the autochtonous fauna from these sites (the autochtonous thanato-or necrocenoses) samples from the western side of the foot of the hill (on the left bank of the Vistula river) were taken additicnally just after a flood in summer 1985 .In that time in the outer part of a river meander, sediments rich in shells of molluscs were accumulated, forming an allochtonous thanatocenose (allocenose).The collection comprises totally about 2000 shells~ more than 1.5 thousand of them derives from the sites 1 -9 described below {Fig.1).
1. Lawns and flower-beds on the courtyard of the castle, between the buildings in the ridge-crest of the hill, in front of the Wawel-Cathedral.The grass is often grazed and on the cultivated flower-beds various garden plants, some of them exotic are introduced.The habitat in question is sunny and only scarce, small places within this are partly shaded by shrubs.The assemblage of gastropods found here consists of seven 'species, but only Cepaea nemoralis (Linnaeus) is represented by several shells (Tab.1).
2. Small lawns and flower-beds in the western part of the ridge--orest, extending between the gate and buildings.The habitat is distinctly differentiated because the cultivated area is divided by low calcareous walls and steps partly over9rown with ivy (Hedera helix).Some places are shaded by deciduous trees and shrubs.The molluscan assemblage comprises 13 species of snails.F i~e of them: Vallonia costata (O.F.MUller), Vallonia pulchella (O .F. MUller), Laciniaria biplicata (Montagu), Cepaea nemoralis (Linnaeus) and Ox~chilus depressus (Sterki) are represented by numerous shells (Tab.1).The occurrence of Truncatellina claustralis (Gredler), a rare ~pecies found at the Wawel hill in the described locality only is noteworthy .From this site derive also single shells of two other species: Punctum pygmaeum (Draparnaud) and Aegopinella pura (Alder), absent at the other sites.
3. The North-western slope of the hill, lying u"der the castle-wall above the Podzamcze street.The site is shaded by numerous tress and bushes but in its lower part an open lawn predominates.Close to the 4. The low , eastern slope of the hill, just above the Podzamcze street.There is a small grazed lawn partly shaded by some trees.The small distance of the stre&t causes a significant pollution of the site.The molluscan assemblage is poor and represented mainly by numerous shells of Vallonia costata (O.F.MUller).Only one specimen of Oxychilus inopinatus (Ulicny) was found also in this localit.y(Tab .1).  6.The sout~ward eiposed slope covered with grass, reach i ng just above a path leading to the principal gate of the castle.This is a xerothermic sunny and dry habitat, often grazed, unfavourable for most of the species of snails.The assemblage is poor and its dominant component is Helicella obvia (Menke).The species forms an abundant population here ( tab. 1).
7. The lower part of the slope, passing southwards down to the Bernardyrtska street.This is a grazed lawn partly shaded by shrubs.The assemblage of snails comprises 13 species , but only Heli;ella obvia (Menke) is represented by numerous specimens.The presence of several shells of Gec!lioides acic~la (O .F. MUller), as well as some other taxa like Cepaea nemoralis (Linnaeus), Va~lonia costata (O.F.MUller) and Cochlicopa lubrica (O.F .MUller) is noteworthy.One shell of Vertigo alpestris Alder derives only from this locality (Tab.1).
8. The western and South-w.esternslope of the hill .below the castle wall.This is a sunny steep slope with outcrops of Jurassic li~estones.In its •lower part, just ab.()ve the fooJtpath leading onto a terrace covered with grass, the entrance tc a cave ( the so called Dragon Cave) is visible.North-and southwards from the entrance to this cave surroun-de~ ~y totks of JUrassic limestones, the slope is overgrown with grass and weeds, but locally some trees and shrubs occur.The ecological conditions are ve~y variable here due to the existence of both sunny and shady habitats with rocks, limestone steps and well as grass and snrubs .The slope is not often block accumulations as grazed so the site in question resemble s a natural habitat.The molluscan assemblage is rich and comprises 12 taxa.Laciniaria biplicata (Montagu) and Vallonia cos-~ (O .F. MUller ) ere the most numerous compGnents of this assemblage (Tab.1).9. limestone rocks at the foot of the western slope of the hill, just above the Vistula and a path leading along the left bank of the river.Rocks are partly outcropped forming sunny habitats, locally overgrown with shrubs.Malacofauna is poor, it consists of 9 taxa represented by scarce shells.Only one of them -Laciniaria biplicata (Montagu) is common here (Tab.1).

TYPES Of ASSEMBLA£E5
Molluscan assemblages found in 9 localities described differ each other in the number of taxa -Nt and the number of specimens-Ni' as well as in the value of the "Taxon Diversity Index" -TO!.This index is calculated according to the following formula, described by the author (Alexandrowicz 1985) : where ~ is the number of specimens in analysed assemblage and xi -the number of specimens representing each taxon.The value of rot-changes between 0 and 1, meaning less or more differentiated assemblages, called by Evans (1972): specialised (TOI = 0) and generalised (TO! = 1) associations.
In the diagram showing the relation between Nt and Ni two groups of assemblages can be distinguished.One of them comprises poor malacocenoses characterised by a low number of species and specimens (localities 1, 4, 9 as well as 6) while the second one -rich malacocenoses (localities 2, 3, 5, 7, 8).Both groups are distinctly separated in the mentioned diagram (Fig. 2-A).
The relation between the number of taxa -Nt and the diversity index -TOI divides the described asscociations into two groups (fig.2-B).The f i rst one is composed of two samples (1, 6) while the second one of the others.The combination of both the diagrams mentioned enables to distinguish the following types of molluscan assemblages at the Wawel Hill: -poor specialized associations (localities 1, 6) characterizing open, sunn~ less differentiated habitats; -poor generalized associations (localities 4, 9) occurring in different habitats unfavourable for gastropods; -rich generalized associations (localities 2, 3, 5, 7, B) found in habitats partly shady and humid, more favourable for molluscs .
The similarity between all the assemblages coming from the localities described was analysed using two simple methods of numerical taxonomy : the qualitative and the quantitative method, both based on the formulas defined by Steinhaus (Marczewski, Steinhaus 1959) and adapted for paleontology by the author (Alexandrowicz 1977, method 1 and 7).It is worth of attention, that the qualitative analysis has given more interesting and instructive results than the quantitative one.
The dendrogram constructed for the first method divides all the material described into three groups, excluding one separate assemblage from the locality 2 (Fig. }-A).The first group (G -I) comprises habitats corresponding with various ecological conditions, disposed on the southern and south-western slopes of the Wawel Hill.The assemblages 5, 7 and 8 are characterized by numerous taxa and specimens as well as by 1-9 -the snail assemblages from the described localities the high value of the diversity index (generalized associations).Three assemblages (3,4,9) belong to the second grnup (U-1!).The nu~r of species is low here, however, they can be regarded as generalized associations due to the values of TOI.The third ~oup (G-III) is formed by the assemblages from two localities (1, 6) b~ing sunny and intensively cultivated.The cumber of taxa is the lowest here and the low value of TDI defines these associations as specialized ones.The remaining assemblage (site 2)• separated by the dendrogram corresponds with its markedly differentiated habitat.It is a rich generalized association, comprising the high number of taxa and specimens.It differs distinctly from the other rich associations described.
The dendrogram constructed according to the quantitative method di-vide~.allthe associations into four groups (Fig. 3-B).The number of specimens seems to be the most important factor of these pattern .
It should be stressed that the malacofauna of the Wawel Hill is distinctly differentiated.This feature can be expressed by the "assemblages diversity index" -ADI used by the author as: where ~is the number of samples (assemblages), ~ ~ the number of taxa in the whole analysed material and xi -the number of taxa in each sample.Values of this index are •normalized like for the TOI-index.For the association found at the Wawel Hill ADI = 0,60, this means a relatively hirh value of differentiation.The character and distribution ~f the described three group~• of assemblages including the malacofauna from the locality 2 (Fig. >-A) are controlled by such ecological factors as the plant density, the exposition a•nd humidity of sites, the proportions of sunny and shady places as well as by the intensity of such cultivation as grazing, p~oughing and fertilizing.

SPECIES DiiTRIBUTION
Snails of the Wawel Hill are distributed unevenly.Four epecies are represented by more than 200 specimens: Vallonia costata (O.f.MUller), Laciniaria biplicata (Montagu), Helicella obyia (Menke) and Cepaea nemoralis (Linnaeus), two taxa -by more than 100 specimens: Cochlicopa lubrica (O.F.MUller) and Vallonia pulcfiella (O.F.MUller) and the following four -by some dozen of specimens.More than the half of all the species have neen found as single or scarce shells (Tab.1).Cochlicopa lubricella (Porro) was found only in sunny cultivated sites.The species is typical of dry and even xerothermic habitats.
Vertigo alpestris Alder -a single shell was found on the southern slope of the hill.It is known as a lithophilic species living mainly on limestone rocks and walls as well as in block fields and debris covers, overgrown partly with grass and weeds.
Truncatellina cylindrica (Ferussac) is a small snail prefering xerothermic habitats.It occurs on the south-eastern, southern and south--western slopes of the hill (G-I) at sunny sites, mainly in the outcrops of jurassic limestones and below the walls of the castle.Such habitats are typical of this species, known from many localities in the Cracow Upland.
Truncatellina claustralis (Gredler) was recorded from the Cracow region only in the Ojc6w National Park (Urbanski 1973(Urbanski , 1977)).At the Wawel Hill it occurs on a small wall and on flowerbeds at the locality 2. It was probably introduced with plants cultivated here.This mediterranean snail lives in dry sunny and warm habitats, mainly on limestones.
Pupilla muscorum (Linnaeus) occurs in the southern part of the hill (G-I) and at the site 2.This species lives in dry and somewhat humid, open habitats, mainly in meadows and grasslands.It is resistant to intensive grazing.
Vallonia pulchella (O.F.MUller) was found in all the localities excluding G-III.It is more frequent on the southern and southeastern slopes than in the northern part of the hi~l.This species is typical of meadows of somewhat various humidity.It seems to be resistant to grazing and pollution.
Vallonia costata (O.F.MUller) is the most frequent species of the described malacocenose, occurring in all the localities.As the previous one, it was found mainly at the sites of G-I and G-II, while within G-III its shells were noted sporadically.The ecological valency of both the species of Vallonia is similar but V. costata prefers more sunny and dry grasslands than V. pulchella.Both find favourable life conditions in habitats affected by anthropopressure.
Punctum pygmaeum (Draparnaud) is represented by some specimens only on the locality 2. This is a mesophilic taxon living in shady and sunny habitats of various humidity.
Vitrina pellucida (D.F.MUller)-two shells of this catholic species were found at the site 3, in a shady environment just below the wall of the castle.
Aegopinella pura (Alder) is represented only by a single shell in the assemblage from the site 2. It prefers shady habitats.
Oxychilus draparnaudi (Beck) occurs commonly on low walls between buildings on the ridge-crest of the hill (locality 2).Some shells were also found on other localities.This species lives in shady and sunny habitats and was reported from cultivated sites, a.o.from some towns (Matzke 1981, Streib 1984).
Oxychilus inopinatus (Ulicny) -one shell of this snail derives from the north-eastern slope of the hill (locality 4).It prefers dry localities, grasslands and cultivated areas.
Limacidae -scarce shells of slugs have been found in samples taken from some localities.Living slugs were not collected.
Cecilioides acicula (O.F.MUller) was found in all the samples taken at the sites belonging to groups G-I and G-Ill, on dry slopes covered with grazed grass.This species is typical of such habitats, living in soil, mainly in xerothermic environments enriched in carbonates.It is resistant to grazing and cultivation.
Laciniaria biplicata (Montagu) is a single representative of the family Clausiliidae.It is common in the western part of the hill (sites 3, 8) as well as at the site 2 on the ridge-crest.The species in question lives on walls and ruins, sunny rocks as well as on trunks and rocks at shady sites.It was noted from some towns (Streib 1984, Lozek 1985), where it found favourable conditions in gardens, parks and cementaries.
Helicella obvia (Menke) occurs commonly on the southern slope of the hill at localities 6 and 7.It prefers xerothermic grasslands as well as sunny, dry ruderal habitats influenced by industry and then may be regarded as a more or less synanthropic element.
Trichia hispida (Linnaeus) is represented by a single shell found at the site 5.It is known from different types of environments, a.o .from cultivated areas.
Arianta arbustorum (Linnaeus) forms a population in the shady habitat in the north-western part of the hill and was also recorded as scarce shells in some other places.It is connected with shrubs, outcrops of limestones and debris cones, living mainly in light forests.
Cepaea nemoralis (Linnaeus) occurs in all the localities described, forming dense populations on slopes in sunny or shady grasslands and shrurrs as well as on cultivated flower-beds on the ridge-crest.It finds favourable life conditions in artificial habitats like gardens, parks, cementa~ies, overgrown walls and ruins, therefore it seems to be a synanthropic element, well-adapted to conditions prevailing in towns.
Cepaea hortensis (O.F.MUller) is reported as a single shell from the eastern slope of the hill (locality 5).Unlike the previous one this species is more frequent in natural habitats than in cultivated areas.
Helix pomatia Linnaeus was found in all the localities of the Wawel Hill.It occurs both in sunny and shady habitats but is common only at tHe site 5, below the high wall of the castle.Like C. nemoralis it is well -adapted to environments of anthropogenic origin, living often in towns (Matzke 1973, Kosinska 1979, lozek 1985).
Relations between the species of snails found at the Wawel Hill were analysed using the taxonomical method based on the Steinhaus formula mentioned above (the qualitati ve variant of analysis).All the speoies were arranged due to their occurrences us i ng the taxonomical distances -Ost and as a result the dendrogram could have been drawn (Fig. 4).The whole set of the taxa can be discriminated basing on two critical values of dst• defined as: VI = 0.67 and VII = 0.33.The first critical value -v 1 divides the set into two groups, called A and B. One of themgroup A -comprises species occuring in different localities and represented by numerous specimens, while the other -group B -species found as scarce shells at one or a few sites only.The species belonging to the second group (B) can be regarded as the accesory elements of the malacocenose of the Wawel Hill.Inside the group A the second critical value -VII can be applied to distinguish three sub-units: A 1 -grouping species living both in shady and sunny habitats , found in all or almost all the localities analysed (Helix pomatia, Cepaea nemoralis, Vallonia costata, V. pulchella, Cochlicopa lubrica) ; A 2 -grouping two s pecies typical of dry xerothermic habitats (Melicella obvia, Cecilioides acicula); A 3 -grouping two species living in open ennviroments (Pupilla mus-~• Truncatellina cylindrica).
1.0 t .80The remaining three taxa of the group A occur in some localities and are not as common as the species mentioned above.
The dendrogram presented enables a conclusion dealing with eo-occurrence of molluscs in sites under a strong pressure of human activity.There are species of snails characterized by a determined resistancy to cultivation, grazing and polution.Like in other towns they live ln some types of artificial evironments and form assemblages typical of the-se habitats (Matzke 1973, Kosinska 1979, Streib 1984, Lo~ek 1985).These assemblages can be somewhat different from the corresponding associations of natural habitats unaffected by anthropogenic factors.

POPULATION ANALYSIS OF SELECTED SPECIES
Four species of snails represented by considerable numbers of specimens were analysed by means of the type of statistical distrib~tion as well as of the structure and differentiation of their populations.The height of the shells (Cochlicopa, Latiniaria) or the largest diameter of the shells (Helicella, Cepaea) are measured with the accuracy of 0.1 mm and simple statistical indicators of all the sets were calculated.These indicators concern a whole population of each species (P) found at the Wawel Hill as well as its subpopulations collected at particular sites.Each set is characterized by. the number of specimens -~.
the arithmetical mean of the height or diameter of the shell -!• standard error -£, standard deviation -~• differentiation index -~• the range of the mean value at the significance level .05-~ and the range of differentiation at the same level -~ (Tab.2).Subpopulations deriving from particular localities are also characterized by the normalized values of arithmetical mean -Nm.The differences between the distribution of the measured data (M) and the corresponding normal distributinn calculated from the statistical indicators (N) were checked using the Kolmogorov test.The analysed populations of four species described below can be regarded as normally distributed.
1. Cochlicopa lubrica (O.F.MOller).The material analysed was collected in localities 2, 3, 5 and 7.At the remaining sites only a few shells of this species were found.The statistical distribution of the values of the shell height is approximate to the normal distribution (Fig. 5 -M, N).The mean value of this feature is-x = 5.97! 0.08 mm, therefore specimens from the Wawel Hill are relatively small in comparison with the populations described by several authors.Snails living in sites 3, 5 and 7 are somewhat smaler or larger, but they differ significantly neither among each other nor form the mentioned mean value of the whole population (Nm range between -0,18 and +0.30).In contrast, the subpopulation collected at the site 2, in sunny, cultivated habitat comprises considerably smaller shells, what is expressed by the value of Nm = .-0.80 (Fig. 5).The difference examined by the t test can be regarded as statistically significant.2. Laciniaria biplicata (Montagu).Shells taken under consideration were riollected at four sites (2, 3, 5, B).The statistical distribution of the measured character (height of shells) corresponds clearly with the normal distribution (Fig. 6-N, M).The mean value of the shell size is -x = 15.54 + 0.13 mm.This means that specimens living at the Wawel Hill are somewhat smaller than those reported from many ather localities.The considerable differentiation of size in the analysed subpopulations can be observed.The shells from sites 2 and 5 (Nm = -0.69 and -0.62) are smaller • than those from 3 and B (Nm = +0.2Band +0.26).The statistically significant difference between this two pairs of sets can be established using the! test (Fig. 6).
3. Helicella obvia (Menke).The subpopulations of this species derive from sites 6, 7 and B. The diameters of the collected shells are low in comparison with the data given in various papers.The mean value of the shell diameter is -x = 12.67 ~ 0.22 mm and the largest specimens reach to 15.5 mm.The whole population is characterized by a distribution approximate to the normal one (Fig. 7-M, N).At two localities (6 and 7) the size of shell is similar to the arithmetical mean cited, therefore the normalized values are: Nm = +0.11and +0.18.At the third locality (~ite B) shells of the mentioned snail are consiaerably smaller (Nm = -0.66),which is confirmed by the! test (Fig. 7).
4. Cepaea nemoralis (Linnaeus).The population described was collected at four localities (1, 2, 7, B).Its distribution does not differ from the normal one (Fig. B-M, N).The diameters of shells are somewhat higher then reported by some authors, reaching the mean value -x = 22.90 .! 0. 24 mm.In the described subpopulations the considerable variability of this value can be observed (Fig. B).The shell diameters of the specimens living in sites 1 and B are close to the mean value (Nm = +0.24and +0.16).In contrast the specimens from the locality 7 are much larger (Nm = +0.7B)while those from the locality 2 are remarkably smaller (Nm = -0.59).
The differentiation of the four populations described suggests that the shell size of the particular snail species is controlled by unstable ecological conditions in habitats of anthropogenic origin.It is worth of noting, that in intensively cultivated habitats species like Cochlicopa lubrica, Laciniaria biplicata and Cepaea nemoralis form the populations consisted of the specimens smaller than those occurring in environments of more natural character.The locality 2 may be an instructive ~ample.In habitats less changed by the human activity (localities 3 and B) shells reach the size similar to the mean value of ), Helicella obvia can be mentioned as an exception (Fig. 7).This snail is typical of ruderal, xerothermic habitats, being quite resistant to pollution, grazing and cultivation.
FLOOD ACCUMULATION OF SHELLS .
In the western part of the foot of the Wawel Hill some recent sediments rich in shells of molluscs were found.They are deposlted on the left bank of the Vistula river as a result of the flood in summer 1985.Shells occured together with fragments of timber, boughs, fruits and plants as well as with anthropogenic mat~rial.The collection derives from the locality 10, situated on the ~iver bank (Fig. 1).Over 500 specimens of living molluscs aQd of empty shells were accumulated on a small bench just over the footpath.The following species were found: Viviparus viviparus (Lir:maeus), Bi thynia tentaculata (Linnaeus), Bi thynia-operculum, Caryc~ium tridentatum (Risso), Physa acuta Draparnaud, Lymnaea peregra (D.The assemblage in question represents the allochtonous thanatocenose, called allocenose, accumulated during a short time.Water molluscs derive mainly from the Vistula river but also from small water bodies existing on both the river banks along the valley.Hygrophilic snails live now just above the river in the flood plain and on the lower terrace.Other land snails were washed out from different habitats of the valley between Cracow and O~wi~cim, flooded in summer 1985.Assemblages like this are often found in Holoceffi and Pleistocene river sediments.Its structure can be illustrated by double diagram according to the method described by Lotek (1964}, called: MSS -malacospectrum of species and MS! -malacospectrum of specimens.It is expressed in the form of a circular diagram, in which the interior circle corresponds to the MSS spectrum while the external circle -to the MS! spectrum and the radiuses of both circles shpw the number of elements (species and specimens} in the logarithmic scale. The allocenose from the Wawel Hill comprises all the ecological groups of molluscs (Fig. 9).The MSS spectrum shows, that the land snails are important components of 'the assemblage (67% of taxa).These are mainly the snails living in shady and partl y shady environments (ecological group 2) as wel l as the snails of open hab i tats (ecological group 5), the mesophilic species from less or more humid sites (ecological group 7 and B) and the hygrophilic snails (ecological group 9).The share of water molluscs reacnes 33%.The proportions in the MSI spectrum are differant.The specimens of the water molluscs are the prevailing tomponenf ot tha assemblage (56%).The ~onsiderab1e number of shells of Physa acuta Draearnau~ ( 42%~ is the most interesting feature of th~ assemblage in q~stion.This snail was introduced to the Vistula due to the progressing pollution of the rivet and the industrial activity.It forms s~ populations near the power station in Skawina, and empty shells of this taxon occur in a great number in the recent sed i ments near Tyniec (Alexandrowicz 1986 ) .The considerable share of shells of hy~ropn i lic snails (14%1 represented mainly by Zoni~oid~s nitidus (O.F.MUller), Trifhia ;ri~\osul~ (Rossm~ssler) and Monachoides rubiginosa (A.Sc~midt) is worth of Rating.These taxa can be often found on the lower terrace along the valley.

CONCLUSIONS
Malacd{ auna inhabiting the Wawel Hill in Cracov comprises more than 20 species of sna1ls.They form some different assemblages, connected With more or less cmtivated, ~razed and ~olluted sites.TKe life conditions on the sl~pes and ridge-crest of the hill are distinctly differentiated.They con~ol the range of poor-special i zed associations, Poor-generalized associations and rich-general!2edassociations, distinguished basing on the number of taxa and specimP.nsas well as on the diversity index TOI.The associatis mentioned were also analysed using tne taxonomlcal method.'me d1s trtbution of part1eular speet~s 1n ~he localities described is clearly uneven, only three of them have been found in all the samples.The occurrence of Truncatellina claustralis (Gre~ler) -a species known in Poland only from scare, isolated sites is worth of noting.Another interesting taxon -Oxyphilu~ draparnaudi (Beck) was reported from some other towns.The populations of four selected species were analysed in details by means of simple statistical methods.The results indicate, that the size of shell is controled partly by natural ecological conditions and partly by effects of human activity.Particular species react differently to changes caused by the

Fig . 1 .
Fig .1.The plan of t~e Wawel Hill, a -the localities described in the text, b -roads, 5. The lawn covering a high , steep slope and a small part of the flat terrace in the south-eastern part of the hill, near the crossing of Grodzka and Bernardy~ska streets.This is an open, sunny habitat and Tab

Fig. 2 .
Fig. 2. The diagrams of the interrelations between the number of taxons (Nt)• the number of specimens (Ni), and the taxon diversity index (TDI): 1-9 -the snail assemblages from the described localities

Fig. 3 .
Fig. 3.The dendrograms of the taxonomical arrangement of snail assemblages: Athe •dendrogram drawn according to a qualitative method (dst coefficient), B -the dendrogr am drawn according to a quantitative method (dSA coefficient), 1-9 -the snail assemblages from the described localities

Fig. 4 .
Fig. 4. The dendrogram of the taxonomical arrangement of snail species corresponding to their occurrence at the Wawel Hill: v 1 , v 11 -the critical values of the dendrogram, A(A 1 , A 2 , A 3 ), B -the taxonomical groups described in the text

Table 2
Statistical features of populations of selected species